The hair bundle provides mechanosensory receptors in the auditory and vestibular systems with a detector that is sufficiently sensitive to respond to a displacment of atomic dimensions. The extraordinary sensitivity of such systems is commonly thought to be limited by noise. This proposal addresses the possibility that noise could in fact enhance the response of the auditory system via a phenomenon of stochastic resonance (SR). A variety of elegant experimental approaches have been proposed to describe noise at different stages of the auditory chain and to examine the potential role for SR at these steps. This study promises to widen our view of sensory systems and their limitations and will further our understanding of how these extraordinary systems accomplish their difficult task of detecting weak signals in a noisy world.